Segment reporting (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Aug. 01, 2014 segment	Aug. 02, 2013 segment	Aug. 01, 2014 segment	Aug. 02, 2013 segment
Segment reporting
Number of reportable segments	1	1	1	1
Net sales data for classes of similar products
Net sales	$ 4,724,039	$ 4,394,651	$ 9,246,120	$ 8,628,384
Consumables
Net sales data for classes of similar products
Net sales	3,576,189	3,301,826	7,021,654	6,496,732
Seasonal
Net sales data for classes of similar products
Net sales	593,596	575,891	1,135,028	1,105,172
Home products
Net sales data for classes of similar products
Net sales	285,428	265,405	569,025	531,216
Apparel
Net sales data for classes of similar products
Net sales	$ 268,826	$ 251,529	$ 520,413	$ 495,264